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United States Patent | 5,686,683 |
Freed | November 11, 1997 |
An additive sound synthesis process for generating complex, realistic sounds is realized in a computationally efficient manner. In accordance with one aspect of the invention, polyphony is efficiently achieved by dosing the energy of a given partial between separate transform sums corresponding to different channels. In accordance with another aspect of the invention, noise is injected by randomly perturbing the phase of the sound, either on a per-partial basis or on a transform-sum basis. In the latter instance, the phase is perturbed in different regions of the spectrum to a degree determined by the amount of energy present in the respective regions of the spectrum. In accordance with yet another aspect of the invention, a transform sum representing a sound is processed in the transform domain to achieve with great economy effects achievable only at much greater expense outside the transform domain. Other transforms besides the Fourier transform may be used to advantage. For example, use of the Hartley transform produces comparable results but allows transforms to be computed at approximately twice the speed as the Fourier transform.
Inventors: | Freed; Adrian (Berkeley, CA) |
Assignee: | The Regents of the University of California (Oakland, CA) |
Appl. No.: | 551889 |
Filed: | October 23, 1995 |
Current U.S. Class: | 84/625; 84/603; 84/622 |
Intern'l Class: | G01H 007/00; G01H 007/10 |
Field of Search: | 84/604-607,622,625,603 381/51 |
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